On-site heavy metals analysis is accomplished using a technique called X-ray Fluorescence (XRF). There are a number of XRF instruments available that are suitable, but it is important that they are supplied with soil calibrations. The latest generation XRF analysers can also detect the lighter elements such as Ca, Mg and Al. The detection limits for the metals is in the % range, but for the toxic heavy metals, the detection limits have been improved compared to analysers available just a few years ago. X-ray Fluorescence (XRF) instruments work by exposing a sample to be measured to a beam of X-rays. The atoms of the sample absorb some of this X-ray energy and become temporarily excited, emitting secondary X-rays upon returning to their ground states. Each chemical element emits x-rays at a unique energy and by measuring the intensities and energies of the emitted X-rays, an XRF analyser can provide qualitative and quantitative analysis regarding the composition of the material being tested.